Heat exchange apparatus



July 20, 14937. A. HAssELBAcH 2,087,344

HEAT EXCHANGE APPARATUS Filed NOV. 13, 1934 :hanche-:wc tim mmm PatentedJuly 20, 1937 YUNITED STATES HEAT EXCHANGE APPARATUS AlexanderHasselbach, Dessau, Germany, assignor to G. Polysius,Aktiengesellschaft, Dessau,

Germany, a firm Application November 13, 1934, Serial No. 752,872 InGermany November 15, 1933 Claims.

- This invention relates to heat exchange apparatus and is moreparticularly concerned with apparatus for the burning or calcining ofcement and similar materials. It is the principal Aobject 5 of theinvention to provide apparatus of this character which will improve theefficiency of conventional kilnsby utilizing a greater proportion of theheat introduced or developed in the kiln and which will deliver thematerial to the l0 kiln in a partly treated' or burned condition wherebythe length of the kiln or the period of treatment of the materialtherein may be substantially lessened and a smaller quantity of fuelwill suice.

It is a more specic object of the invention to provide, in combinationwith a kiln which may be of the usual rotary type, a device associatedwith the inlet end of the kiln but arranged exteriorily thereofnwithinwhich the material may be gas. In the preferred form of the inventionthis device comprises a support for the material which is mounted forrotation independently of the kiln and which is permeable to the gas,means -being provided to introduce the exhaust kiln gas above thematerial on the support and to withdraw the gas downwardly through thematerial and the support, whereby the material may be subjected directlyto the action of the hot gas andl will at the same time protect thesupport from excessively high temperatures.

Further objects and features of the invention will b'e apparent from thefollowing description taken in connection with the accompanying drawing,in which Figure 1 is a vertical sectional view of apparatus embodyingthe principles of the invention;

and

, Figures 2, 3, and 4 are sectional views of modied forms of the gaspermeable support shown in Figure 1.

It will be observed that in the drawing the invention is illustrated asapplied to a conventional rotary kiln a, this being the preferredembodiment of the invention. It will nevertheless be .understood thatthe application to other types of kiln is contemplated. A chamber d,within'which the material is subjected to preliminary treatment, isprovided with a discharge chute c leading into the inlet end of thekiln, the chamber and chute being preferably stationary, conventionalmeans being associated with the kiln and chute whereby the kiln may berotated without the escape of gas except through the chute.

Within the chamber d is supported a drum b,

subjected tothe action of the hot exhaust kiln.

the drum having a gas permeable periphery and being preferablycylindrical in shape. The longitudinal axis of the drum is preferablydisposed in a generally horizontal direction, the drum being supported,for instance, on a shaft e which may be rotated in any convenientmanner. Extending through one end wall of the chamber d and drum b is aninlet chute g through which the material to be treated may be introducedinto the drum.

At its lower side'the chamber d may be provided with a downwardlydirected, generally conical portion f leading to a conduit i throughwhich gas may be withdrawn from the chamber, a fan h or other suitabledevice being preferably associated with the conduit i for this purpose.

In View of the simplicity of the apparatus, the mode of operation willbe quite apparent. The material to be treated, for instance raw cementmaterial or the like, is introduced through the d inlet chute g, isdeposited on the lower side of the gas permeable support or drum b andis gradually displaced toward the left-hand end from whence it isdischarged through the chute c into the kiln a for the final burning.The hot exhaust gas from the kiln a passes' in the opposite directionthrough the chute c, the contraflow principle being thus employed, flowsinto the drum b immediately over the layer of material therein, and isdrawn downwardly through the material and through the drum anddischarged through the conduit z'. In this manner the material in thedrum is subjected to the very high temperature of the exhaust kiln gasand heat which would otherwise be 4wasted is rendered effective forpartial preliminary burning or calcining of the material. -Since thedrum bis disposed exteriorly of the kiln a and since the peripheral wallof the drum is protected by the layer of material thereon, rapiddestruction of i comprising a cylindrical -casing which is suitablyperforated for the passage of gas, but it will be understood that ascreen or wiremesh or other construction suited to the, materialundergoing treatment may be employed.

Dealing nowwith Figure 2, it will be observed that exible metallicelements in the form of chains k are secured to the opposite end wallsof the drum and dependent therefrom so as to sweep through the layer ofmaterial at the lower side of the drum when the latter is rotated. Itwill be appreciated that these chains absorb a considerable portion ofthe heat of the exhaust kiln gases and by passing through the materialto be treated convey this heat to the material. Furthermore, it will beobvious that the chains are effective in preventing the formation ofundesirable lumps of material and serve to spread the material out in afairly thin layer and to facilitate the movement of the material fromone end of the drum to the other. It will of course be appreciated thatother devices of a structurally different nature but performinggenerally the same function as the chains specifically disclosed hereinmay be employed, for instance loosely disposed metallic elements orother well-known heat exchange or transmission bodies.

In Figure 3 an arrangement is illustrated in which the chains aresupported at one end from the peripheral wall of the drum b at pointsspaced circumferentially and longitudinally thereof. In Figure 4 thechains are simply laid in the bottom of the drum. Various combinationsof these arrangements of the chains are of course possible.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. In apparatus for effecting preliminary treatment of material to beburned in a kiln, the combination with the kiln, of a drum separate fromand disposed exteriorly of said kiln and adjacent the inlet end of thekiln for rotation about a generally horizontal axis, said drum having agas permeable yperipheral'wall affording a support for the material,means for discharging the material from the drum into the kiln and forconveying exhaust gas from the kilny into the drum, gas-tight meansclosely surrounding the peripheral wall of said drum above the normallevel of the material therein, and means for withdrawing gas from thedrum in a downward direction through the material and the peripheralwall of the drum.

2. In apparatus for making cement and similar products, the combinationwith a preburning chamber, of a gas permeable support Within saidchamber, said support comprising a rotatable drum, the wall of saidchamber closely surrounding the peripheral wall of said drum above thenormal level of the material therein, a kiln ar- 'products, thecombination with a preburning chamber, of a gas permeable support withinsaid chamber, said support comprising a rotatable drum, the wall of saidchamber closely surrounding the peripheral wall of said drum above thenormal level of the material therein, exible heat I exchange membersdisposed within said drum, a kiln arranged to receive the material fromsaid support for causing the burning of the material, said support beingseparate from and disposed outside said kiln, means whereby saidmaterial is delivered from the support to the kiln, and means forcausing a current of hot gas to flow downwardly through said support andthe material thereon to preburn the material.

4. In apparatus for burning cement and like material, the combinationwith a rotary kiln, of a preburning chamber separate from said kiln anddisposed adjacent the kiln inlet and exteriorly of the kiln, a rotatinggas permeable support for the material within said chamber, means fordelivering material onto the support, means for discharging materialfrom the support into the kiln and for conveying hot exhaust kiln gasfrom the kiln to a zone directly above the material on the support,means for inhibiting the passage of gas through the portion of saidsupport not normally covered by said material, and means for withdrawingthe exhaust gas downwardly through the material and the support.

5. In apparatus for effecting preliminary treatment of material to beburned in a kiln, the combination with-the kiln, of a drum separate fromand disposed exteriorly of said kiln and adjacent the inlet end of thekiln for rotation about. a generally horizontal axis, said drum having agas permeable peripheral wall affording a support for the material,means for discharging the material from the drum into the kiln and forconveying exhaust gas from the kilnr into the drum, gas-tight meansclosely surrounding the peripheral wall of said drum above the normallevel of the material therein, means for withdrawing gas from the drumin a downward direction through the material and the peripheral wall ofthe drum, and chains secured to the drum and suspended therein.

ALEXANDER HASSELBACH.

